Title

DIRECT AND INDIRECT REDUCTION AND CARBURIZATION OF REDUCED IRON IN IRON ORE-CARBON COMPOSITE PELLETS HEATED AT ELEVATED TEMPERATURES

DIRECT AND INDIRECT REDUCTION AND CARBURIZATION OF REDUCED IRON IN IRON ORE-CARBON COMPOSITE PELLETS HEATED AT ELEVATED TEMPERATURES

Authorship

IGUCHI, YOSHIAKI; ENDO, SATOSHI; YOKOMOTO, SHOHEI

IGUCHI, YOSHIAKI

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ENDO, SATOSHI

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YOKOMOTO, SHOHEI

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DOI

10.5151/2594-357x-34Red-531-540

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Abstract

Iron ore-carbon composite pellets of 3.5 mm and 18 mm in diameter were prepared inside a rotating tire of pelletizer. The reaction rates of 3.5 mm pellets heated in vacuum were gravimetrically measured and the rates of 18 mm pellets heated in nitrogen flow were measured by analyzing the outlet gas by infrared gas analyzer. The solid-solid reactions between iron oxide and carbon measured in vacuum were very fast, especially after metallic iron started to form, and the rate was the faster the better the crystallity of carbon, i.e. graphite, coke and coal char. The reduced iron pellets after just reactions finished by heating in nitrogen flow were repeatedly cleaned in ethanol under ultrasonic vibration and analyzed by combustion method. The content of carburized iron depended on the crystallinity of carbon as well as in vacuum but the carbon content were hardly carburized over the carbon content of the solidus line of Fe-C binary system because of liberation of the carbon particles during the coalescence of reduced iron ore particles, which proceeded faster as the carbon content approaches the solidus line. The carburization through the gas phase is a minor route.

Iron ore-carbon composite pellets of 3.5 mm and 18 mm in diameter were prepared inside a rotating tire of pelletizer. The reaction rates of 3.5 mm pellets heated in vacuum were gravimetrically measured and the rates of 18 mm pellets heated in nitrogen flow were measured by analyzing the outlet gas by infrared gas analyzer. The solid-solid reactions between iron oxide and carbon measured in vacuum were very fast, especially after metallic iron started to form, and the rate was the faster the better the crystallity of carbon, i.e. graphite, coke and coal char. The reduced iron pellets after just reactions finished by heating in nitrogen flow were repeatedly cleaned in ethanol under ultrasonic vibration and analyzed by combustion method. The content of carburized iron depended on the crystallinity of carbon as well as in vacuum but the carbon content were hardly carburized over the carbon content of the solidus line of Fe-C binary system because of liberation of the carbon particles during the coalescence of reduced iron ore particles, which proceeded faster as the carbon content approaches the solidus line. The carburization through the gas phase is a minor route.

Keywords

direct reaction, carburization, coalescence

direct reaction, carburization, coalescence